spatial_audio_2d/
spatial_audio_2d.rs

1//! This example illustrates how to load and play an audio file, and control where the sounds seems to come from.
2use bevy::{
3    audio::{AudioPlugin, SpatialScale},
4    color::palettes::css::*,
5    prelude::*,
6    time::Stopwatch,
7};
8
9/// Spatial audio uses the distance to attenuate the sound volume. In 2D with the default camera,
10/// 1 pixel is 1 unit of distance, so we use a scale so that 100 pixels is 1 unit of distance for
11/// audio.
12const AUDIO_SCALE: f32 = 1. / 100.0;
13
14fn main() {
15    App::new()
16        .add_plugins(DefaultPlugins.set(AudioPlugin {
17            default_spatial_scale: SpatialScale::new_2d(AUDIO_SCALE),
18            ..default()
19        }))
20        .add_systems(Startup, setup)
21        .add_systems(Update, update_emitters)
22        .add_systems(Update, update_listener)
23        .run();
24}
25
26fn setup(
27    mut commands: Commands,
28    mut meshes: ResMut<Assets<Mesh>>,
29    mut materials: ResMut<Assets<ColorMaterial>>,
30    asset_server: Res<AssetServer>,
31) {
32    // Space between the two ears
33    let gap = 400.0;
34
35    // sound emitter
36    commands.spawn((
37        Mesh2d(meshes.add(Circle::new(15.0))),
38        MeshMaterial2d(materials.add(Color::from(BLUE))),
39        Transform::from_translation(Vec3::new(0.0, 50.0, 0.0)),
40        Emitter::default(),
41        AudioPlayer::new(asset_server.load("sounds/Windless Slopes.ogg")),
42        PlaybackSettings::LOOP.with_spatial(true),
43    ));
44
45    let listener = SpatialListener::new(gap);
46    commands.spawn((
47        Transform::default(),
48        Visibility::default(),
49        listener.clone(),
50        children![
51            // left ear
52            (
53                Sprite::from_color(RED, Vec2::splat(20.0)),
54                Transform::from_xyz(-gap / 2.0, 0.0, 0.0),
55            ),
56            // right ear
57            (
58                Sprite::from_color(LIME, Vec2::splat(20.0)),
59                Transform::from_xyz(gap / 2.0, 0.0, 0.0),
60            )
61        ],
62    ));
63
64    // example instructions
65    commands.spawn((
66        Text::new("Up/Down/Left/Right: Move Listener\nSpace: Toggle Emitter Movement"),
67        Node {
68            position_type: PositionType::Absolute,
69            bottom: px(12),
70            left: px(12),
71            ..default()
72        },
73    ));
74
75    // camera
76    commands.spawn(Camera2d);
77}
78
79#[derive(Component, Default)]
80struct Emitter {
81    stopwatch: Stopwatch,
82}
83
84fn update_emitters(
85    time: Res<Time>,
86    mut emitters: Query<(&mut Transform, &mut Emitter), With<Emitter>>,
87    keyboard: Res<ButtonInput<KeyCode>>,
88) {
89    for (mut emitter_transform, mut emitter) in emitters.iter_mut() {
90        if keyboard.just_pressed(KeyCode::Space) {
91            if emitter.stopwatch.is_paused() {
92                emitter.stopwatch.unpause();
93            } else {
94                emitter.stopwatch.pause();
95            }
96        }
97
98        emitter.stopwatch.tick(time.delta());
99
100        if !emitter.stopwatch.is_paused() {
101            emitter_transform.translation.x = ops::sin(emitter.stopwatch.elapsed_secs()) * 500.0;
102        }
103    }
104}
105
106fn update_listener(
107    keyboard: Res<ButtonInput<KeyCode>>,
108    time: Res<Time>,
109    mut listener: Single<&mut Transform, With<SpatialListener>>,
110) {
111    let speed = 200.;
112
113    if keyboard.pressed(KeyCode::ArrowRight) {
114        listener.translation.x += speed * time.delta_secs();
115    }
116    if keyboard.pressed(KeyCode::ArrowLeft) {
117        listener.translation.x -= speed * time.delta_secs();
118    }
119    if keyboard.pressed(KeyCode::ArrowUp) {
120        listener.translation.y += speed * time.delta_secs();
121    }
122    if keyboard.pressed(KeyCode::ArrowDown) {
123        listener.translation.y -= speed * time.delta_secs();
124    }
125}
spatial_audio_2d/spatial_audio_2d.rs

spatial_audio_2d/
spatial_audio_2d.rs
